Radiotherapy is an important treatment for many types of cancer. This technique relies on the use of radiation sources to deliver dose to a target region within the patient's body. Furthermore, radiotherapy is not restricted only to cancer treatment, but can be applied in general to deliver dose to a target region within the patient's body as in the case, for example, of radiosurgery.
In the state of the art, radiotherapy is, in most of the cases, performed using radio frequency accelerators, which are devices capable of delivering electron or gamma beams with energy typically in the range 6-30 MeV. Due to their technology, these devices usually deliver very wide beams on the order of 10×10 cm2 and a dose rate of few Gy/min. Typically, such devices deliver to the target region 0.1-1 mGy per pulse, at a frequency of few hundreds Hz. Treatments with these devices usually last at least few minutes. During this time the target region within the patient's body can move, due, for example, to patient's breathing. For this reason huge effort is put in imaging the target region during the treatment.
U.S. Pat. No. 9,044,604 discloses a radiotherapy system including a radiotherapy module and at least one X-ray imaging module. Using radio frequency accelerators, due to the low dose per pulse and to the high number of pulses needed, it is not feasible to perform radiography at each irradiation step. One of the reasons is that each radiography delivers additional dose to the patient.
U.S. Pat. No. 8,039,819 discloses a device for creating a spatial dose distribution in a medium volume, the device comprising a laser system and at least one electron source for releasing a plurality of high-energy quasi-monoenergetic electron pulses upon irradiation with said laser pulses. The disclosed device produces ultra-short radiation pulses (<1 ms) with very high energy (>50 MeV), but it is lacking a synchronized imaging system and a feedback control that exploits the treatment effectiveness due to the shortness of the radiation pulses.